5. "I have five lessons on Monday." a. Mary says that b. Mary said that

Решение:

Преобразуем прямую речь в косвенную. Прямая речь содержит глагол "have" (Present Simple). Вводная конструкция "Mary says" – Present Simple, "Mary said" – Past Simple. При переходе в косвенную речь, если вводная конструкция в Past Simple, время глагола изменяется на Past Simple (Present Simple -> Past Simple).

• 5.a. Mary says that she has five lessons on Monday.
• 5.b. Mary said that she had five lessons on Monday.

Ответ:

• 5.a. Mary says that she has five lessons on Monday.
• 5.b. Mary said that she had five lessons on Monday.